Pop-up Ads & Malware: Are You Safe?

TL;DR

Closing a pop-up ad quickly doesn’t guarantee you’re safe. Some ads can start downloading malware before you even react. Prevention (ad blockers, cautious browsing) is far better than trying to close them fast.

Understanding the Risk

Pop-up ads are a common nuisance, but they can also be dangerous. Here’s how they might install malware, even if you shut them down quickly:

• Drive-by Downloads: Some malicious ads automatically start downloading software to your computer as soon as the page loads – before you click anything.
• Exploit Kits: These ads look for weaknesses in your browser, operating system or plugins and try to install malware through them.
• Social Engineering: Ads might trick you into clicking something (like a ‘Close’ button that’s actually an installation link).

What Happens When You Close a Pop-up?

When you close a pop-up, your browser attempts to stop the ad’s process. However:

• Downloads in Progress: If an ad has already started downloading something, closing the window might not stop it. The download could continue in the background.
• Scripts Running: Malicious scripts embedded in the ad can sometimes continue running even after you close the pop-up.

Steps to Protect Yourself

1. Install an Ad Blocker: This is the most effective solution. Popular options include uBlock Origin, Adblock Plus and Ghostery. Most browsers have ad blocker extensions available.
   • Chrome Example: Go to Chrome Web Store, search for ‘uBlock Origin’, and install it.
   • Firefox Example: Go to Firefox Add-ons, search for ‘uBlock Origin’, and install it.
2. Keep Your Software Updated: Regularly update your browser, operating system, and plugins (like Flash – though avoid using Flash if possible). Updates often include security patches.
   • Windows Update Example: Search for ‘Windows Update’ in the Start menu and check for updates.
3. Be Careful What You Click: Avoid clicking on suspicious links or buttons within pop-up ads, even if they appear to be a ‘Close’ button.
4. Use a Reputable Antivirus Program: A good antivirus program can detect and remove malware that might have been installed by an ad. Regularly scan your computer.
5. Browser Security Settings: Configure your browser’s security settings to block pop-ups and potentially harmful content.
   • Chrome Example: Go to Chrome Settings > Privacy and security > Site Settings > Pop-ups and redirects – ensure ‘Blocked (recommended)’ is selected.
   • Firefox Example: Go to Firefox Options > Privacy & Security > Block pop-up windows – ensure the checkbox is ticked.

What If You Think You’ve Been Infected?

1. Run a Full System Scan: Use your antivirus program to perform a full scan of your computer.
2. Check for Suspicious Programs: Look in your list of installed programs (Control Panel > Programs and Features on Windows, Applications folder on macOS) for anything you don’t recognize.

   control /name "Programs and Features"

3. Use a Malware Removal Tool: Consider using a dedicated malware removal tool like Malwarebytes.
4. Reset Your Browser: As a last resort, you can reset your browser to its default settings (this will remove extensions, cookies and other data). Be aware this will delete customisations.

Final Thoughts

While quickly closing a pop-up might sometimes work, it’s not a reliable defense against malware. Proactive measures like ad blockers and safe browsing habits are crucial for protecting your cyber security.